Polymers such as PMMA, PE, or even PEEK are an ideal alternative as substitute materials of metallic or ceramic materials. Thus, they can be used for spinal, orthopedic or dental implants. They offer many advantages such as an absence of interferences with scanners, a biomechanical behavior similar to that of bone, a proved biocompatibility . . . . The preferred biocompatible polymer is PEEK (Polyether Ether Ketone), a thermoplastic polymer.
However, these polymers are unfortunately non radiopaque to X-rays. They are hardly detected when used in spinal, orthopedic or dental implants. Moreover, it is also difficult to detect their localisation when used in dental restorative materials, for instance, in case of accidental ingestion.
To the applicant's knowledge and to avoid this drawback, there is nowadays only one radiopaque PEEK polymer made with barium sulfate (BaSO4) fillers. This compound is a white solid oxide, usually highly pure, used as an opacifier in paintings or as “boiled barium” in medical radiology, particularly for gastrointestinal tract monitoring.
Although such filled polymers have radio-opacity property, the radio opacity level remains quite low making them difficult to be detected, unless the fillers concentration is increased significantly. However, such concentration may cause final material having lower final mechanical properties. In addition, its high refractive index together with the large size of particles leads to a final product which is opaque to light or has a diminished aesthetic appearance. As already said, filled polymers have lower mechanical properties than unfilled polymers.